Question

Bài 1 Tính\(\frac{A}{B}\)biết

a)A=\(\frac{1}{1.300}+\frac{1}{2.301}+\frac{1}{3.302}+...+\frac{1}{101.400}\)

B=\(\frac{1}{1.102}+\frac{1}{2.103}+\frac{1}{3.104}+...+\frac{1}{299.400}\)

b)A=1/2+1/3+1/4+...+1/200

B=1/199+2/198+3/197+...+199/1

c)A=1-1/2+1/3-1/4+...+1/2007-1/2008

B=1/1005+1/1006+1/1007+...+1/2007+1/2008

Answer 1

a) 299A = \(1-\frac{1}{400}\) A= \(\frac{399}{400}\) :299     

    101B = \(1-\frac{1}{400}\) B = \(\frac{399}{400}\):101

\(\frac{A}{B}=\frac{299}{101}\)

Làm tắt ý a, mấy ý kia biết làm nhưng dài lắm

Answer 2

b = \(\frac{1}{200}\)

c =1